Field of the Invention
The present invention relates to a boring head, and particularly to a device for automatically balancing a rotary boring head used for finishing high precision bores.
Description of Related Art
Boring heads for finishing high precision bores typically include a cartridge with a cutting insert that is radially adjustable to set the boring head diameter and to maintain the tool diameter necessary to compensate for wearing of the cutting insert. Typically, the boring head only has a single position where the center of gravity of the movable parts of the boring and the center of gravity of the cartridge are balanced about the rotation axis of the boring head. Adjustment of the cartridge and cutting insert can cause unbalancing of the boring head, which may lead to undesirable geometric deviations of the bore during the machining process. Minimizing such deviations is critical for such processes. Furthermore, boring heads are commonly used at higher cutting speeds where even a small imbalance is exaggerated thereby further increasing the need for the tool to be properly balanced.
Certain boring head designs have addressed this problem by providing a balancing ring that is adjusted manually to properly balance the boring head. Other boring head designs, such as the one shown in U.S. Pat. No. 8,727,678, include a system that automatically balances the boring head during adjustment of the cutting tool. This automatic balancing arrangement, however, includes a complex mechanism that is expensive to manufacture and provides an arrangement with an inherent imbalance along the length of the rotational axis.